4-Kb page-size for kernel in ARM-Cortex

4-Kb page-size for kernel in ARM-Cortex

[Uma shankar]

Hi,

          It is my understanding that  in ARM, the MMU setting for
kernel VA  range ( 0xc0000000 onwards )
is set up using the section-sized mapping ( 1 Mb in size ) ,  as this
range maps to a  contiguous physical address range.

I am trying out a memory-checking tool on Cortex.    This tool has the
requirement that it  needs to be able to set up  PTE for each 4 Kb
range of  kernel address.

So,  paging_init ( arch/arm/mm/mmu.c ) is modified for this.

But , with this MMU setting,   the kernel hangs somewhere  after
freeing init memory. ( "freeing init mem"  is the last print I see on
console. )

For  3-level page-table setting of kernel VA,  do I have to change
something else also ?

              thanks

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Re: 4-Kb page-size for kernel in ARM-Cortex

[Minchan Kim]

On Thu, Jun 03, 2010 at 08:13:35PM +0530, Uma shankar wrote:
> Hi,
> 
>           It is my understanding that  in ARM, the MMU setting for
> kernel VA  range ( 0xc0000000 onwards )
> is set up using the section-sized mapping ( 1 Mb in size ) ,  as this
> range maps to a  contiguous physical address range.
> 
> I am trying out a memory-checking tool on Cortex.    This tool has the
> requirement that it  needs to be able to set up  PTE for each 4 Kb
> range of  kernel address.
> 
> So,  paging_init ( arch/arm/mm/mmu.c ) is modified for this.
> 
> But , with this MMU setting,   the kernel hangs somewhere  after
> freeing init memory. ( "freeing init mem"  is the last print I see on
> console. )
> 
> For  3-level page-table setting of kernel VA,  do I have to change
> something else also ?

It's related to arm architecture. 
Please, Cced linux-arm-kernel mailing list. 
Maybe they can solve your problem. 

P.S) 
Please send your patch with question, symptom more detail and oops 
if you can get it. 


> 
>               thanks
> 
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-- 
Kind regards,
Minchan Kim

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Re: 4-Kb page-size for kernel in ARM-Cortex

[Minchan Kim]

My bad. wrong address. correct it. 

On Fri, Jun 04, 2010 at 09:32:34PM +0900, Minchan Kim wrote:
> On Thu, Jun 03, 2010 at 08:13:35PM +0530, Uma shankar wrote:
> > Hi,
> > 
> >           It is my understanding that  in ARM, the MMU setting for
> > kernel VA  range ( 0xc0000000 onwards )
> > is set up using the section-sized mapping ( 1 Mb in size ) ,  as this
> > range maps to a  contiguous physical address range.
> > 
> > I am trying out a memory-checking tool on Cortex.    This tool has the
> > requirement that it  needs to be able to set up  PTE for each 4 Kb
> > range of  kernel address.
> > 
> > So,  paging_init ( arch/arm/mm/mmu.c ) is modified for this.
> > 
> > But , with this MMU setting,   the kernel hangs somewhere  after
> > freeing init memory. ( "freeing init mem"  is the last print I see on
> > console. )
> > 
> > For  3-level page-table setting of kernel VA,  do I have to change
> > something else also ?
> 
> It's related to arm architecture. 
> Please, Cced linux-arm-kernel mailing list. 
> Maybe they can solve your problem. 
> 
> P.S) 
> Please send your patch with question, symptom more detail and oops 
> if you can get it. 
> 
> 
> > 
> >               thanks
> > 
> > --
> > To unsubscribe, send a message with 'unsubscribe linux-mm' in
> > the body to majordomo@kvack.org.  For more info on Linux MM,
> > see: http://www.linux-mm.org/ .
> > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
> 
> -- 
> Kind regards,
> Minchan Kim

-- 
Kind regards,
Minchan Kim

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